While talking with his mother on how to handle the North should it come to conflict with the Starks, Prince Joffrey muses on crushing the Northerners with a new "Royal Army" and giving Winterfell to his great-uncle Kevan to rule over. Though, Cersei dismisses the plan as impractical. Kevan is also indirectly (and inaccurately) accused of being a "half-wit with a stutter" by King Robert when he taunts Lancel about his alliterative name.[2]

Kevan is going over troop movements with his brother Tywin in their army's command tent when Tyrion enters, having escaped from his capture by Catelyn Stark, and with a makeshift army of hill tribesmen in tow. Kevan is pleasantly surprised to see Tyrion safe and free, though Tyrion's own father seems mildly disappointed at both prospects. Kevan explains that Jaime crushed the Tully army at the Battle of the Golden Tooth and is laying siege to Riverrun. Tyrion wonders how King Robert would allow this, but Tywin explains that Robert is dead and Eddard Stark imprisoned. A messenger then arrives saying that Robb Stark's army has passed south of the Neck. Tywin orders Kevan to have the drummers signal the army to assemble to march, and to send word to Jaime that their army will be moving against Robb.[3]

Kevan is later part of Tywin's pre-battle strategy meeting, in which Tywin declares that Tyrion and his hill tribe allies will be in the vanguard. Tyrion balks at this, not only because it will put him in the greatest danger, but because the hill tribes are inexperienced at pitched battle. Kevan tries to console his nephew that the hill tribes do seem to be rather ferocious, and should be up for it. Kevan takes part in the following Battle of the Green Fork, and Tywin's army is victorious. Even Tyrion and his hill tribes did fairly well. It turns out, however, that this was simply a diversionary force so Robb could use the bulk of his army to ambush the western half of the Lannister army under Jaime at Riverrun.[4]

Following the Lannister defeat at the Battle of the Whispering Wood and the capture of Jaime, Kevan joins Tywin's council as they discuss their next move. Kevan points out that with the Starks attacking from the north and both of Robert Baratheon's brothers attacking in southern Westeros, they are facing a war on two fronts. With half of their armies destroyed, Kevan asks if they should consider negotiating with Robb Stark for peace. Tyrion bluntly points out that all chance for a negotiated peace died with Robb's father Eddard, whom Joffrey petulantly had executed. Tywin angrily orders everyone out, except for Tyrion. He agrees that they could have negotiated if Eddard was still alive, but now they cannot hold their position, so he and Kevan will lead their remaining army-group south to regroup at Harrenhal.[5]

Ser Kevan is present at a war council held at Tywin's chambers at Harrenhal; he predicts that King’s Landing will fall an hour after King Stannis Baratheon's forces arrive. Kevan counsels Tywin to order Cersei and her family to flee to the safety of Casterly Rock. Tywin balks at surrendering the Iron Throne. Kevan argues that giving up the throne is better than seeing the heads of their relatives mounted on the city gates, fearing that Stannis will execute any Lannister he finds in the city. Tywin rejects the suggestion, believing that a king who runs cannot remain king for long.[6]

Tywin complains that Stannis is just two days from King's Landing while Robb Stark is on their doorstep in the Westerlands. Kevan reports word from their scouts that Robb remains north of Ashemark. Tywin laughs derisively and says that the last time their scouts assured them of Robb's movements they were lured into a trap. Tywin blames their poor intelligence for the capture of Jaime. Tywin asserts that Robb has gotten too close to Casterly Rock. Kevan relays news that Robb has sent a splinter force to recapture Winterfell and theorizes that the Greyjoys' seizure of the castle is a boon to them because Robb will not march against Casterly Rock until he is at full strength. Tywin dismisses the suggestion and opts to march on the Westerlands, leaving the defense of the capital to his allies.[6]

Following his brother's death, Kevan is present at Tywin's wake alongside his son Lancel. He apologizes to Cersei for the appearance of his son, who has joined a religious group known as the Sparrows. Kevan believes that religion has its place, but he dismisses them as "bloody fanatics" and states that they never would have set foot in the capital while Tywin was alive.[7]

Kevan sits on the Small Council when Cersei announces that she is taking over control of the body until the King chooses a new Hand of the King. After appointing Lord Mace Tyrell as the new Master of Coin, Qyburn as the new Master of Whisperers and dismissing Grand MaesterPycelle's and Mace Tyrell's request to be appointed acting Hand, Cersei offers Kevan the new position of Master of War, in his capacity as leader of the Lannister armies in the wake of Tywin's death. Kevan demands to hear the news of his appointment from King Tommen himself but Cersei says that she is speaking in his name for the time being and that he is learning what it means to be a ruler from Cersei.

Angered by her blatant seizure of power at her son's detriment and by her addition of sycophants such as Qyburn to the Small Council, Kevan refuses to recognize her authority and informs her that, in his eyes, she is the Queen Mother, nothing more. As he stands to leave, Cersei angrily berates him for abandoning the King in his time of need. Kevan tells her that, should the King ask for him, he would be waiting for him at Casterly Rock before leaving the Small Council chamber.[8]

Following Cersei's arrest by the High Sparrow, Grand Maester Pycelle sends a raven to Casterly Rock to summon Kevan back to King's Landing to serve as the Hand of the King. Kevan now presides over the small council. When Cersei asks Qyburn to ask Kevan to come to see her in her cell, Qyburn says he already asked and Kevan refused.[9]

Kevan is present alongside Pycelle when Cersei returns to the Red Keep after her walk of atonement. Kevan remains stern and silent as Qyburn fawns over Cersei, presumably having not yet forgiven her for disgracing his son Lancel.[10]

In the A Song of Ice and Fire novels, Ser Kevan is a solid, reliable, and serious man. His appearance in the books is different: Kevan being blonde, green-eyed, bearded and somewhat fat. He is content with living in his elder brother's shadow, serving as a follower and not trying to usurp Tywin's authority. This does not, however, mean that Kevan is an unintelligent man, simply that he recognizes Tywin's superior capabilities, and he occupies a position of power and responsibility in House Lannister as Tywin's most trusted lieutenant.

Kevan is loyal to his brother, loves his wife and children, and is proud of his family and heritage. He is married to the Lady Dorna of House Swyft. As well as Lancel he has two younger sons, Willem and Martyn, and an infant daughter, Janei. Tyrion always got along much better with his uncle Kevan than his tyrannical father Tywin, as well as having a good relationship with his younger two uncles (Kevan's younger brothers) Tygett and Gerion (who are both deceased by the time the books begin). Kevan always displays the basic courtesy and family respect to Tyrion that Tywin does not.

Kevan's son Willem and his cousin Tion Frey were taken captive by the Starks in the Battle of the Whispering Wood, imprisoned at Riverrun, and killed by Rickard Karstark. Kevan's son Martyn was captured in the Battle of Oxcross and later Robb exchanged him for Robett Glover, who was taken captive by the Lannisters in the Battle of Duskendale. The TV series, however, had Lord Karstark kill both Martyn and Willem. Tion Frey was actually the younger son of Genna Lannister, Tywin and Kevan's sister, but the TV series hadn't introduced her by Season 3. Moreover, Genna's oldest son Cleos Frey was changed in the TV adaptation to be "Alton Lannister", a more distant cousin. Apparently, the TV producers didn't want viewers to be confused - at the time - why someone named "Frey" would be fighting for the Lannisters (given that this was before the Freys betrayed the Starks at the Red Wedding). Thus, similar to how Cleos Frey was changed around, the TV series killed both of Kevan's younger sons instead of only one.

Kevan doesn't appear in Season 3 and 4 whereas in the third novel he is present at several important events: he participates in the Battle of the Blackwater and is later made Master of Laws. He becomes consumed by worry and grief due to the death of his son Willem, the sickness of Lancel, and Martyn's captivity. He is present at Tyrion and Sansa's wedding. During the small council meeting in which the Red Wedding is reported and it is Kevan, not Varys, who reminds Joffrey that Sansa is his aunt-by-marriage when the King shares his plan to have Robb Stark's head served to her. After Tyrion is arrested for being accused of murdering Joffrey, it is Kevan, not Jaime, who sees Tyrion in the cell for several times; he informs Tyrion about the judges, and offers to help Tyrion to find any witness that the latter requests; Tyrion asks him uncle to find Podrick Payne, whom Kevan brings to him; Sansa, whom no one in King's Landing can find; and Varys, who is already summoned by Cersei as her witness. It is also Kevan who relay Tywin's offer to Tyrion the offer that allow him to join the Night's Watch in exchange for a plea for mercy. Later Kevan is present at the trial by combat of Tyrion, in which Gregor Clegane brutally kills Oberyn Martell.

Following Tywin's death, Kevan is not offered the position of "Master of War" - which doesn't exist in the novels as the "supreme commander" of the realm's armies is whoever holds the title of "Protector of the Realm" - but that of Hand of the King, which he rejects as Cersei refuses to name him Regent - the title she holds. The "Master of War" title however, could be a reference to how Cersei starts basically making up titles on the Small Council.

According to Tyrion, "the gods shaped him to be a follower, not a leader, well the gods and my lord father", and thinks that Kevan never had a thought that Tywin had not had first. It turns out, however, that many underestimated him: in truth he always did as his older brother instructed because Tywin was a political and military genius, so Kevan happened to agree with his decisions most of the time. This loyalty and obedience only extended to Tywin, so when he realizes that Cersei is running House Lannister into the ground, he quickly turns against her.

To spite him, Cersei names her cousin Daven Lannister, son of Stafford Lannister, as the new Warden of the West while the title of Castellan of Casterly Rock is given to Ser Damion Lannister, another cousin from Stafford's branch of the family. Following Cersei's arrest, Kevan returns to King's Landing, but serves as Lord Regent and Protector of the Realm instead of Hand of the King. The title of Hand of the King is granted to Mace Tyrell (who did not go to Braavos in the books) in order to appease House Tyrell. Kevan takes steps to repair the damages Cersei caused with her plots, and to prevent her from ruining Tommen as she had Joffrey.

Unlike in the show, Kevan visits the imprisoned Cersei and confronts her angrily for corrupting Lancel. He tells her that she must perform the walk of atonement, and informs her of the latest bad news, among them about Myrcella (injured severely by Ser Gerold "Darkstar" Dayne, survived but was horribly disfigured).

Following the walk of atonement, Kevan does not gloat at Cersei but feels sorry for her. Recalling a similar event that he witnessed many years ago, he muses sadly that his elder brother never dreamed that his own daughter would have to go through the same humiliating punishment he imposed on his father's mistress.

"Kevan" is pronounced like the common real-life name "Kevin", as opposed to "Kee-van", etc.[2]